Rosa Paulina Calvillo-Medina1, Diana Gabriela Ponce-Angulo2, Tania Raymundo3, Carlos Adolfo Müller-Morales4, Efraín Escudero-Leyva5,6, Juan Campos Guillén1, Victor Manuel Bautista-de Lucio2. 1. Laboratorio de Microbiología Molecular, Universidad Autónoma de Querétaro, Santiago de Querétaro, Mexico. 2. Departamento de Microbiología y Proteómica Ocular, Instituto de Oftalmología "Fundación de Asistencia Privada Conde de Valenciana", Mexico City, Mexico. 3. Laboratorio de Micología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, Mexico. 4. Departamento de Córnea y Cirugía Refractiva, Instituto de Oftalmología "Fundación de Asistencia Privada Conde de Valenciana", Mexico City, Mexico. 5. Centro de Investigaciones en Productos Naturales (CIPRONA) y Escuela de Biología, Universidad de Costa Rica, San José, Costa Rica. 6. Centro Nacional de Innovaciones Biotecnológicas (CENIBiot), y Centro Nacional de Computación Avanzada (CNCA), CeNAT-CONARE, San José, Costa Rica.
Abstract
BACKGROUND: Infectious keratitis is the main cause of preventable blindness worldwide, with about 1.5-2.0 million new cases occurring per year. This inflammatory response may be due to infections caused by bacteria, fungi, viruses or parasites. Fungal keratitis is a poorly studied health problem. OBJECTIVES: This study aimed to identify a new fungal species by molecular methods and to explore the possible efficacy of the three most common antifungals used in human keratitis in Mexico by performing in vitro analysis. The capacity of this pathogen to cause corneal infection in a murine model was also evaluated. METHODS: The fungal strain was isolated from a patient with a corneal ulcer. To identify the fungus, taxonomic and phylogenetic analyses (nrDNA ITS and LSU data set) were performed. An antifungal susceptibility assay for amphotericin B, itraconazole and voriconazole was carried out. The fungal isolate was used to develop a keratitis model in BALB/c mice; entire eyes and ocular tissues were preserved and processed for histopathologic examination. RESULTS AND CONCLUSION: This fungal genus has hitherto not been reported with human keratitis in Mexico. We described a new species Purpurecillium roseum isolated from corneal infection. P roseum showed resistance to amphotericin B and itraconazole and was sensitive to voriconazole. In vivo study demonstrated that P roseum had capacity to developed corneal infection and to penetrate deeper corneal tissue. The global change in fungal infections has emphasised the need to develop better diagnostic mycology laboratories and to recognise the group of potential fungal pathogens.
BACKGROUND:Infectious keratitis is the main cause of preventable blindness worldwide, with about 1.5-2.0 million new cases occurring per year. This inflammatory response may be due to infections caused by bacteria, fungi, viruses or parasites. Fungal keratitis is a poorly studied health problem. OBJECTIVES: This study aimed to identify a new fungal species by molecular methods and to explore the possible efficacy of the three most common antifungals used in humankeratitis in Mexico by performing in vitro analysis. The capacity of this pathogen to cause corneal infection in a murine model was also evaluated. METHODS: The fungal strain was isolated from a patient with a corneal ulcer. To identify the fungus, taxonomic and phylogenetic analyses (nrDNA ITS and LSU data set) were performed. An antifungal susceptibility assay for amphotericin B, itraconazole and voriconazole was carried out. The fungal isolate was used to develop a keratitis model in BALB/c mice; entire eyes and ocular tissues were preserved and processed for histopathologic examination. RESULTS AND CONCLUSION: This fungal genus has hitherto not been reported with humankeratitis in Mexico. We described a new species Purpurecillium roseum isolated from corneal infection. P roseum showed resistance to amphotericin B and itraconazole and was sensitive to voriconazole. In vivo study demonstrated that P roseum had capacity to developed corneal infection and to penetrate deeper corneal tissue. The global change in fungal infections has emphasised the need to develop better diagnostic mycology laboratories and to recognise the group of potential fungal pathogens.